ringing chord

A unique characteristic of barbershop music that occurs when the four voices are tuned in a way that creates an audible sympathetic pitch or fifth note sounding the third harmonic. This pitch is different from, and higher in pitch from, the fundamental pitches being sung by the quartet. Any major chord that a quartet sings producing clear overtones can be considered a ringing chord. The ringing chord is also known as the expanded sound, the angel's voice, or the fifth voice. This sound is created by singing a chord that is tuned using just intonation in a way that the harmonic series of each sounded note is in tuned with the harmonic series of each of the other notes. In other words, the performers take advantage of the overlap in common overtones of each note in the chord and creates the audible sympathetic pitch or fifth note. Additionally, the notes being sung should be part of the harmonic series of the other notes, and the vowel sounds of the words being sung must be identical.